In both Iowa and Illinois auto accident cases, the fact that one party got a ticket for his involvement in the case does not come into evidence.
What does come in, is a guilty plea. If the party pays the ticket, that comes into evidence in a later civil trial as an admission of guilt.
The person will have an opportunity to explain why they paid the ticket, however. This is why you need to ask him about the ticket at the deposition.
“I’m handing you what’s been marked as deposition exhibit 1. Do you recognize it?”
“What is it?”
“It’s a ticket I got from this accident.”
“And that ticket was for failure to stop at a stop sign?”
“Is that your signature on the back of it?”
“So you pled guilty to the ticket, correct?”
(now the key question)
“Did you do that because you felt you were guilty?”
Why do you ask that question? Because many people will say “yes” and this eliminates other explanations (ie it was just easier than going to court) at the time of trial. If they have another explanation during the dep, so what? You’re not out anything for having asked.